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Masoudi P.,Iranian Offshore Oil Company IOOC | Masoudi P.,University of Tehran | Arbab B.,Offshore Oil Company IOOC | Mohammadrezaei H.,Offshore Oil Company IOOC | Mohammadrezaei H.,Iranian Offshore Oil Co. IOOC
Journal of Petroleum Science and Engineering | Year: 2014

Determining productive zones has always been a challenge for petrophysicists. On the other hand, Artificial Neural Networks are powerful tools in solving identification problems. In this paper, pay zone determination is defined as an identification problem, and is tried to solve it by trained Neural Networks. Proposed methodology is applied on two datasets: one belongs to carbonate reservoir of Mishrif, the other belongs to sandy Burgan reservoir. The results showed high precision in classifying productive zones in predefined classes with Classification Correctness Rate of more than 85% in both geological conditions. Applicability of proposed pay zone determination procedure in carbonate environment is a great advantage of developed methodology. Fuzzified output, being independent of core tests and verification with well tests results are of other advantages of the Neural Network-based method of pay zone detection. © 2014 Elsevier B.V.


Ahmadi M.A.,Petroleum University of Technology of Iran | Ebadi M.,Islamic Azad University at Tehran | Yazdanpanah A.,Iranian Offshore Oil Company IOOC
Journal of Petroleum Science and Engineering | Year: 2014

Liquid production from gas condensate reservoirs, which is an important economic and technical issue, depends on the thermodynamic conditions underlying the porous media. Accurately estimating the relevant parameters is an incentive for researchers to develop and propose a diversity of correlations; however, certain correlations are not sufficiently precise compared with correlations that are routinely applied to determine the dew point pressure (Pd). Due to numerous misunderstandings in Pd estimations, which are typically observed in upstream industries, great effort was expended herein to produce a high-performance method to monitor the Pd. The solution was produced by creating a hybrid of two effective and robust methods, the swarm intelligence and artificial neural network (ANN) models. The proposed model was extended using precise dew point pressure data reported in previous studies; moreover, based on these data, the evolved intelligent approach and conventional schemes were compared. The statistical results show a notable performance by the smart model in determining the dew point pressure of condensate gas reservoirs. Based on the reliable results, which are highly accurate and effective, it can logically be inferred that implementing the proposed approach, PSO-ANN, can aid in better understanding reservoir fluid behavior through reservoir simulation scenarios. © 2014 Elsevier B.V.


Masoudi P.,University of Shahrood | Masoudi P.,Iranian Offshore Oil Company IOOC | Masoudi P.,University of Tehran | Asgarinezhad Y.,University of Shahrood | Tokhmechi B.,University of Shahrood
Arabian Journal of Geosciences | Year: 2014

The more accurate feature identification, the more precise reservoir characterisation. Porosity, permeability and other rock properties could be estimated and classified by analytical and intelligent methods. Feature selection plays a vital role in the process of identification. In this work, two goals are followed: first, developing Bayesian Network, K2 algorithm, as a complementary means (not an alternative) to find interrelationships of petrophysical parameters and second, feature conditioning for estimating porosity and permeability, vug and fracture detection, and net pay determination. Due to the results, bulk density log is introduced as the most important feature for characterizing the reservoir because it is found useful for identifying all the studied reservoir features. © 2014 Saudi Society for Geosciences.


Heidary S.,Shahid Beheshti University | Dehghan A.A.,Iranian Offshore Oil Company IOOC | Zamanzadeh S.M.,University of Tehran
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2016

Miscible gas injection is an approved profitable process that could significantly enhance oil recovery from different types of reservoirs while the major factor affecting its efficiency would be the minimum miscibility pressure (MMP) value. A recent experimental technique, known as vanishing interfacial tension (VIT), can estimate the MMP for gas–oil mixtures by measuring interfacial tension values and extrapolating them to zero at a sequence of pressures. Compositional simulation models are also useful in MMP determination by tuning an equation of state to compute the realistic phase behavior of reservoir fluid. In this paper, the capability and quality of MMP prediction via different methods such as laboratory slim tube tests, VIT technique, compositional simulation, and various empirical correlations were examined using a light oil sample taken from an Iranian carbonate reservoir, employing two pure gases of CO2 and N2 as the injectants. The accuracy and validation of the mentioned methods were then confirmed successfully by obtaining negligible overall absolute deviation percentages (AD%) compared with the conducted slim tube tests results. © 2016 Taylor & Francis Group, LLC.


Gholami R.,Curtin University Australia | Moradzadeh A.,University of Tehran | Rasouli V.,Curtin University Australia | Hanachi J.,Iranian Offshore Oil Company IOOC
Journal of Applied Geophysics | Year: 2014

Conventionally, high frequency Dipole Shear sonic Imager (DSI) logs are used for anisotropic modeling where fast and slow shear wave's velocities are required. However, the results obtained from a DSI log are restricted to a specific and possibly short interval of the wellbore. The aims of this paper are to use Vertical Seismic Profile (VSP) data and show its application in geomechanical analysis of subsurface layers under anisotropic condition. After processing and separating upgoing and downgoing P- and S-waves, a methodology based Vertical Transverse Isotropic (VTI) condition was presented to determine elastic stiffness parameters. Having stiffness parameters determined, elastic modulus, strength and in-situ stress parameters were estimated and calibrated against the field and core sample data. Although the VSP based geomechanical parameters were calibrated against the real field data, the accuracy of the method cannot be as much as that of the well logs. However, the method presented in this paper may become a very good asset for geomechanical evaluation of the intervals where well log data are not available. © 2014 Elsevier B.V.


Mehrabi H.,University of Tehran | Rahimpour-Bonab H.,University of Tehran | Hajikazemi E.,Iranian Offshore Oil Company IOOC | Jamalian A.,University of Tehran
Facies | Year: 2015

In the Zagros area and the Persian Gulf, Upper Cretaceous carbonate sequences are among the most important hydrocarbon reservoirs. In this study, facies analysis and stratigraphic interpretation of these sequences, Cenomanian-Santonian in age, have been carried out in subsurface sections from various parts of the Zagros area (including the Dezful Embayment and Fars Province) and the Persian Gulf. To have a better understanding about the facies variations at the regional scale, depositional facies of these formations have been determined and grouped as facies associations. Frequency analyses of depositional facies and their characteristics reveal considerable variations in the study area. These are interpreted to have resulted from the combined effects of paleoenvironmental conditions and platform configuration. The overall depositional model of these formations is that of a carbonate ramp, which was likely homoclinal for the Sarvak and distally-steepened for the Ilam Formation. The isopach maps of the studied intervals are depicted based on the available data from hundreds of drilled wells, surface sections and seismic interpretations. Large scale variations in facies and thicknesses of the studied formations are interpreted to be controlled by regional tectonic evolution and sea-level fluctuations during the Upper Cretaceous. © 2015, Springer-Verlag Berlin Heidelberg.


Zohoorparvaz A.,Iranian Offshore Oil Company IOOC | Arastoo A.,Pars Oil And Gas Company | Sahraei E.,University of Tabriz
Petroleum Science and Technology | Year: 2013

Waterflooding in heterogeneous heavy oil reservoirs usually encounters the unfavorable mobility ratio resulting in early breakthrough and poor sweep efficiency. In such condition, injection of a viscous pre-flush is recommended. For this purpose, the use of emulsions as a mobility control agent has been studied here. Investigating the proper rheological behavior of invert water-in-oil emulsions, four different samples with 50%, 60%, 70%, and 80% water-cut were prepared and more stable products were injected into high permeable heavy oil saturated waterflooded sandpacks. Experiment results revealed that invert water-in-oil emulsions with high viscosities could help displacement process and increase oil recovery factor. © 2013 Copyright Taylor and Francis Group, LLC.


Alinezhad K.,University of Mazandaran | Alinezhad K.,Iranian Offshore Oil Company IOOC | Hosseini M.,University of Mazandaran | Movagarnejad K.,University of Mazandaran | Salehi M.,Iranian Offshore Oil Company IOOC
Korean Journal of Chemical Engineering | Year: 2010

In many ways, the use of high electrostatic fields in the separation of water-in-oil emulsions is a mature technology, with most developments arising from attempts to improve the process of crude oils, in terms of the separation of water, salt or other hydrophilic impurities. In this way, different mechanisms have been proposed until now and several parameters have been studied to estimate the level of separation. In this work, after a review of the process and its application, new results are presented for AC currents under non-uniform electrical fields (dielectrophoresis) on the water-in-crude oil emulsion. Then the effects of voltage, temperature, volume fraction and API are studied on degree of separation. Finally, a correlation is presented among these parameters by an experimental model. © 2010 Korean Institute of Chemical Engineers, Seoul, Korea.


Sani R.R.,Iranian Offshore Oil Company IOOC | Afsari M.,Iranian Offshore Oil Company IOOC | Amani M.,Texas A&M University at Qatar
SPE Middle East Oil and Gas Show and Conference, MEOS, Proceedings | Year: 2011

This article investigates the effects of block to block interaction, gravity drainage and capillary continuity, on oil recovery from South Pars oil layer during primary production and gas flooding. For choosing the best oil production and EOR scenarios, the necessity of investigations like this study is obvious. In addition this work can be extended to other Iranian fractured reservoirs. Sensitivity analyses during primary production and immiscible gas injection are performed by using CMG/IMEX simulator1 based on a very simple single porosity model but very close to dual porosity/permeability modules of this simulator. The objectives of this article are: Investigation of main matrix-fracture fluid exchange mechanisms (like gravity drainage and capillary imbibition) during primary production from South Pars oil ring and gas injection into South Pars oil ring. Emphasizing the importance of issues such as capillary continuity between matrix blocks, reinfiltration of fluid from higher to lower blocks and block shape on flow processes and oil recovery during primary production and immiscible gas injection in South Pars oil layer. By characterizing the fractured/non-fractured reservoirs and finding the main oil recovery mechanisms, reservoir management can be done scientifically at the best time and at the best location. Copyright 2011, Society of Petroleum Engineers.


Allahyarzadeh M.H.,Iranian Offshore Oil Company IOOC | Zendehdel N.,Iranian Offshore Oil Company IOOC | Dehghan P.,Iranian Offshore Oil Company IOOC | Ahdeno F.,Iranian Offshore Oil Company IOOC | Kavid J.,Iranian Offshore Oil Company IOOC
Journal of Loss Prevention in the Process Industries | Year: 2015

The aim of this paper is to suggest an effective procedure to eliminate a major deficiency in impressed current cathodic protection (CP). Current work describes performed activities through jetty cathodic protection troubleshooting as a case study. Although CP troubleshooting is straightforward, sometimes it is very complicated and confusing. To eliminate the appeared imperfection, different procedures were carried out; the root cause of the trouble in the system was shown to be in reversed current. Here the current which passed throughout installed junction were measured to survey reversed current. Current work offers a new approach in CP troubleshooting. © 2014 Elsevier Ltd.

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